"Well, it goes barreling into this dark narrow cavern-like tunnel. The pee-nee ship's job is to shoot a little thingy so that it will penetrate the large spherical Death Star. Watch Luke grunt a little sigh when he shoots his little thingy successfully." Really folks, you need to watch the scene in this context. I am not making this up.

"Then a 'chain reaction' occurs. The big sphere ultimately bursts into a thousand points of light, and all the good guys jump for joy!"